We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Research. Validation of the shake test for detecting freeze damage to adsorbed vaccines.
- Authors
Kartoglu, Ümit; Özgüler, Nejat Kenan; Wolfson, Lara J.; Kurzatkowski, Wieslaw
- Abstract
Objective To determine the validity of the shake test for detecting freeze damage in aluminium-based, adsorbed, freeze-sensitive vaccines. Methods A double-blind crossover design was used to compare the performance of the shake test conducted by trained health-care workers (HCWs) with that of phase contrast microscopy as a “gold standard”. A total of 475 vials of 8 different types of World Health Organization prequalified freeze-sensitive vaccines from 10 different manufacturers were used. Vaccines were kept at 5 °C. Selected numbers of vials from each type were then exposed to .25 °C and .2 °C for 24-hour periods. Findings There was complete concordance between HCWs and phase-contrast microscopy in identifying freeze-damaged vials and non-frozen samples. Non-frozen samples showed a fine-grain structure under phase contrast microscopy, but freeze-damaged samples showed large conglomerates of massed precipitates with amorphous, crystalline, solid and needle-like structures. Particles in the non-frozen samples measured from 1 ìm (vaccines against diphtheria–tetanus–pertussis; Haemophilus influenzae type b; hepatitis B; diphtheria–tetanus–pertussis–hepatitis B) to 20 ìm (diphtheria and tetanus vaccines, alone or in combination). By contrast, aggregates in the freeze-damaged samples measured up to 700 ìm (diphtheria–tetanus–pertussis) and 350 ìm on average. Conclusion The shake test had 100% sensitivity, 100% specificity and 100% positive predictive value in this study, which confirms its validity for detecting freeze damage to aluminium-based freeze-sensitive vaccines.
- Publication
Bulletin of the World Health Organization, 2010, Vol 88, Issue 8, p624
- ISSN
0042-9686
- Publication type
Academic Journal
- DOI
10.2471/BLT.08.056879